Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.util.Scanner;
import java.util.Vector;

public class J {   
   
    static class ProblemSolver{
        public void solveTheProblem(InputReader in,PrintWriter out){
        Scanner s= new Scanner(System.in);
        int n=s.nextInt();
        int m=s.nextInt();
        int [][] a= new int[n][m];
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++)
                a[i][j]=s.nextInt();
        }
        if(n>m){
            Vector row=new Vector();
            Vector col=new Vector();
            int []b = new int[m];
            for(int i=0;i<m;i++){
                int mi=a[0][i];
                for(int j=1;j<n;j++){
                    if(mi>a[j][i])
                        mi=a[j][i];
                }
                b[i]=mi;
                for(int j=0;j<mi;j++){
                    col.add(i+1);
                }
            }
            for(int i=0;i<m;i++){
                for(int j=0;j<n;j++)
                    a[j][i]-=b[i];
            }
            for(int i=0;i<n;i++){
                if(a[i][0]!=0){
                    int mi=a[i][0];
                    for(int j=0;j<mi;j++){
                        row.add(i+1);
                    }
                    for(int j=0;j<m;j++){
                        a[i][j]-=mi;
                    }
                }
            }
            boolean f=true;
            for(int i=0;i<n;i++)
                for(int j=0;j<m;j++)
                    if(a[i][j]!=0)
                        f=false;
            if(!f){
                System.out.print(-1);
            }
            else{
                System.out.println(row.size()+col.size());
                for(int i=0;i<row.size();i++){
                    System.out.println("row "+ (row.get(i)));
                }
                for(int i=0;i<col.size();i++){
                    System.out.println("col "+ col.get(i));
                }
            }
        }
        else{
            Vector row=new Vector();
            Vector col=new Vector();
            int []b = new int[n];
            for(int i=0;i<n;i++){
                int mi=a[i][0];
                for(int j=1;j<m;j++){
                    if(a[i][j]<mi)
                        mi=a[i][j];
                }
                b[i]=mi;
                for(int j=0;j<mi;j++)
                    row.add(i+1);
            }
            for(int i=0;i<n;i++)
                for(int j=0;j<m;j++)
                    a[i][j]-=b[i];
            for(int i=0;i<m;i++){
                if(a[0][i]!=0){
                    int mi=a[0][i];
                    for(int j=0;j<mi;j++)
                        col.add(i+1);
                    for(int j=0;j<n;j++)
                        a[j][i]-=mi;
                }
            }
            boolean f=true;
            for(int i=0;i<n;i++)
                for(int j=0;j<m;j++)
                    if(a[i][j]!=0)
                        f=false;
            if(!f){
                System.out.print(-1);
            }
            else{
                System.out.println(row.size()+col.size());
                for(int i=0;i<row.size();i++){
                    System.out.println("row "+ (row.get(i)));
                }
                for(int i=0;i<col.size();i++){
                    System.out.println("col "+ col.get(i));
                }
            }
        }
    }
}
   
    //Default template for all the codes
    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream),32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    }
   
    //Main method for all the codes
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        ProblemSolver problemSolver = new ProblemSolver();
        problemSolver.solveTheProblem(in, out);       
        out.close();       
    }

}